2016 年 57 巻 6 号 p. 781-788
Antiferromagnets themselves do not generate either stray fields or spontaneous magnetization. However, if an antiferromagnet is coupled with a ferromagnet, unique and useful characteristics appear. Exchange bias is one such characteristic that is utilized in spintronic devices like spin-valve films. To date, exchange bias has been used to induce static effects in devices; however, the exchange bias has not been switchable in these devices. Recently, switchable exchange bias has been developed using Cr2O3, which exhibits a magnetoelectric effect in an antiferromagnetic layer. The promising features of this effect are (1) the strength of the exchange bias is high and its direction is perpendicular to the film, and (2) the switching is triggered by an electric field. In this overview, we will summarize our recent results on the unique temperature dependence of high, perpendicular exchange bias and magnetoelectric switching of the induced perpendicular exchange bias.
